HTTP 402
The reserved HTTP status code 'Payment Required' first defined in RFC 2068 (1997), carried forward in RFC 2616 and RFC 7231, and revived as the foundation for on-demand payment negotiation on the modern web.
HTTP 402 is an HTTP response status code that was reserved for future use in the original HTTP/1.1 specification. For decades it remained unused in production, but protocols such as x402 now use it to signal that a server requires payment before returning a resource. A client that receives a 402 response reads the payment requirements (chain, token, amount, recipient, facilitator) from response headers, signs a payment payload, and retries the request with a signed-payment header. A facilitator then verifies the signature and settles the payment on-chain before the resource is returned.
Related terms
- x402 - An open payment protocol built on top of HTTP 402 that lets servers demand stablecoin payment before serving a resource, and lets clients (i
- Payment Requirements - The machine-readable description of what a resource server demands for access - chain, asset, amount, recipient, facilitator, and expiry.
- Payment Proof - A signed payment payload submitted with a retried HTTP request authorising the facilitator to settle the required amount on the client's beh
Recent stories
PROTOCOL
- Coinbase Q1 call: 99% of x402 settled in USDC, 90% of agentic stablecoin volume on Base - Choi calls x402 'the open standard for the next wave of agentic commerce' · theglobeandmail.com
- Circle ships Nanopayments on mainnet - gas-free USDC down to $0.000001 across 11 chains, fully x402 v2 compatible · circle.com
- Kite ships mainnet + Agent Passport - first x402-native chain with programmable agent wallets goes live · globenewswire.com
- Utexo enables USDT payments on x402 with near-instant Bitcoin-native settlement · prnewswire.com
- AWS Bedrock integrates x402 - first major cloud provider with native HTTP 402 payment rails for agents · cryptobriefing.com